This invention relates to a spill resistant carpet backing. More particularly, it relates to using a hydrophobic acid-treated inorganic filler or salts thereof as part of an aqueous dispersed polymeric composition to increase the spill resistance of a carpet backing.
Generally, tufted carpets minimally consist of tufted fibers through a primary backing and a precoat. Tufted carpets have a precoat and may also have additional layers such as a laminate layer, a secondary layer, and a foam layer. Moreover, the tufted carpet may have more than one secondary layer. The tufted carpet may be applied to a variety of subfloors, including wood, concrete, and tile.
The precoat is required to anchor the carpet tufts to the primary backing. It may also contain an adhesive to adhere the tufted carpet to additional layers or the subfloor. The precoat can affect the carpet""s tuft bind, hand, delaminating properties, wet strength properties, wear resistance, and barrier performance. Alternatively, a laminate layer may be applied without a precoat and anchor the carpet tufts to the primary backing. But, better anchoring is achieved when a precoat is applied than with a laminate layer is applied alone.
The precoat may be prepared from several materials. However, it is usually prepared from a polyurethane material or a styrene-butadiene latex. It may be prepared from a butadiene-acrylonitrile latex, an ethylene-vinyl acetate latex, a styrene-butadiene-butyl acrylate latex, a chloroprene latex, a polyethylene copolymer latex, an ethylene-styrene latex, a styrene-butadiene-vinylidene chloride latex, a styrene-alkyl acrylate latex, a vinyl latex, or an acrylic latex.
With regard to a polyurethane precoat, conventional practice in the carpet manufacturing industry requires that the precoat be prepared from an isocyanate formulation (A-side formulation) and a polyol formulation (B-side formulation) at the carpet manufacturing site. This is sometimes referred to as xe2x80x9cA+B chemistryxe2x80x9d. Preparing a polyurethane precoat by A+B chemistry can result in unpredictable loss of production and inefficiency due to problems that can occur in carrying out the reaction at the manufacturing site, such as premature gellation.
Alternatively, the polyurethane precoat may be applied as an aqueous polyurethane (PU) dispersion. Aqueous PU dispersions can be prepared by polymerizing the polyurethane reactants in an organic solvent followed by dispersion of the resulting solution in water, and optionally followed by removal of organic solvent. See U.S. Pat. Nos. 3,437,624; 4,092,286; 4,237,264; 4,742,095; 4,857,565; 4,879,322; 5,037,864; and 5,221,710, which are incorporated herein by reference. Also, an aqueous polyurethane dispersion may be prepared by first forming a prepolymer, next dispersing the prepolymer in water, and finally conducting a chain extension in the water as disclosed in WO 98/41552, published Sep. 24, 1998, which is incorporated herein by reference. Preparations of aqueous dispersions of polyurethane are also described in U.S. patent application Ser. Nos. 09/039,978 and 09/039,976. U.S. Pat. No. 4,296,159 to Jenkines, et al., discloses preparing a tufted or woven article having a unitary backing prepared by applying a polyurethane forming composition to the underside of the tufted or woven article.
The precoat may consist of an aqueous styrene butadiene latex. Styrene-butadiene (SB) latexes for use in carpet are described, for example, in P. L. Fitzgerald, xe2x80x9cIntegral Latex Foam Carpet Cushioningxe2x80x9d, J. Coat Fab. 1977, Vol. 7 (pp.107-120); and in R. P. Brentin, xe2x80x9cLatex Coating Systems for Carpet Backingxe2x80x9d, J. Coat. Fab. 1982, Vol. 12 (pp. 82-91). SB latexes provide flexibility in production costs owing to the ability to include low to high concentrations of filler component in a low viscosity latex. However, SB latexes with filer may not, meet the rigorous standards set for intermediate grade carpets. In addition, current technology may require that a latex material remain stable for a period of up to one year. High solids content affects the stability of SB latexes. Accordingly, commercially available SB latexes typically do not have a solids content of greater than 55%.
Without regard to the type of material used to make the precoat, a liquid spill can detrimentally affect the carpet""s performance and appearance. The liquid can flow through the precoat and then onto, or be absorbed by, the underside of the carpet. In particular, spilled liquids such as beverage drinks, food, blood, urine, and feces can penetrate to the underside of the carpet or into the subfloor so that the liquids can be inaccessible by various cleaning methods.
When the precoat is an aqueous polymeric dispersion, various conventional methods are used to provide a moisture or spill resistant barrier between the primary backing and other layers or the subfloor. The conventional methods include (1) modifying the precoat formulation, (2) adding an essentially impermeable membrane between the precoat and the other layers or the subfloor, and (3) applying a spill resistant coating onto the precoat or another layer.
An example of an attempt to improve spill resistance by modifying the precoat formulation is increasing the coating weight of the dispersion. This method is undesirable because it requires more material, which is expensive. It can also yield a final carpet having undesirable hand or stiffness properties. Moreover, the precoat has an increased probability of blistering in the drying ovens.
Another example of an attempt to improve spill resistance by modifying the precoat formulation is adding a wax filler to the dispersion. While the addition of waxes to aqueous styrene-butadiene latexes is known to improve the water barrier properties of the precoat, it is also known that wax additives are generally detrimental to other carpet properties.
Another example of a formulation modification is the reduction of filler levels. But, this formulation change increases the carpet cost and may increase the tendency of the precoat to blister in the drying ovens.
Examples of an attempt to improve spill resistance by adding an essentially impermeable membrane between the precoat and the other layers or the subfloor are described in U.S. Pat. Nos. 4,336,089 and 5,763,040. In U.S. Pat. No. 4,336,089; the patentees describe a water-impervious film that collects the spilled liquid below the carpet surface. In U.S. Pat. No. 5,763,040, the patentees describe applying a non-permeable fabric or film to a carpet backing. This secondary backing prevents liquid flow to subsequent layer or to the subfloor. Unfortunately, both described membranes may permit the spilled liquid to collect at a depth between the carpet and the underlay barrier such that the spilled liquid cannot be removed through traditional cleaning methods.
An example of an attempt to improve spill resistance by applying a spill resistant coating is applying a fluorochemical or another material onto the precoat or another layer. U.S. Pat. No. 5,348,785 describes applying a fluorochemical on the underside of a secondary backing. The use of fluorochemicals to impart water impermeability is also described in U.S. Pat. Nos. 4,619,853 and 4,643,930. Unfortunately, the use of fluorochemicals can increase the cost of the carpet. Additionally, steam or extraction cleaning of a carpet can leach the fluorochemicals out of the carpet.
Other materials that are applied as a spill resistant coating include silicone-based compositions, wax emulsions, naturally occurring oils, and hydrophobic acrylate resins. Applying these various hydrophobic compositions to a secondary backing is described in U.S. Pat. No. 5,558,916, but these compositions do not prevent absorption of spilled liquids by underlying layers.
It would be desirable to prepare a carpet backing that resists penetration by spilled liquids. It would also be desirable to prepare the carpet backing by a process that would not significantly increase the cost of manufacturing the carpet. Further, it would be desirable to prepare a spill resistant carpet backing that can protect the underside of a carpet from spills such that the spilled liquids would be accessible for removal by various cleaning methods.
According to the present invention, a spill resistant carpet backing is provided. More specifically, an aqueous dispersed polymeric composition for preparing the spill resistant carpet backing is provided
In the preferred embodiment, the aqueous dispersed polymeric composition of the present invention comprises an aqueous dispersed polymeric material, an inorganic filler, and a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof. Alternatively, the inorganic filler is pretreated with the hydrophobic compound. Also, a kit and a method for preparing a spill resistant carpet backing from the aqueous dispersed polymeric composition is provided. While the most significant impact on spill resistance is achieved through using the aqueous dispersed polymeric composition as a precoat, the aqueous dispersed composition may be applied as a laminate layer or a foam layer to improve spill resistance.
In the preferred embodiment of the present invention, the aqueous dispersed polymeric composition comprises an aqueous dispersed polymeric material, an inorganic filler, and a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof. The aqueous dispersed polymeric material is selected from the group consisting of a polyurethane dispersion, a styrene-butadiene latex, a butadiene-acrylonitrile latex, an ethylene-vinyl acetate latex, a styrene-butadiene-butyl acrylate latex, a chloroprene latex, a polyethylene copolymer latex, an ethylene-styrene latex, a styrene-butadiene-vinylidene chloride latex, a styrene-alkyl acrylate latex, a vinyl latex, an acrylic latex, and mixtures thereof. The preferred aqueous dispersed polymeric composition is a polyurethane dispersion.
In the present invention, polyurethane can refer to a polyurethane compound, a polyurea compound, or mixtures thereof A polyurethane compound can be obtained by the reaction of a polyol with a polyisocyanate. A polyurea compound can be obtained by the reaction of an amine with a polyisocyanate. A polyurethane compound or polyurea compound can contain both urea and urethane functionality, depending on what compounds are included in the A and/or aside formulations. For the purposes of the present application, no further distinction will be made herein between the polyurethane compounds and polyurea compounds. The term xe2x80x9cpolyurethanexe2x80x9d will be used generically to describe a polyurethane compound, a polyurea compound, and mixtures thereof.
A polyurethane dispersion composition useful in the practice of the present invention includes water, and a polymeric compound selected from the group consisting of a polyurethane compound, a mixture of polyurethane-forming compounds, and mixtures thereof. A polyurethane dispersion as described herein can include chain extenders, surfactants, fillers, dispersants, foam stabilizers, thickeners, fire retardants, defoamers, and other materials useful in polyurethane formulations.
Polyurethane-forming compounds as used in the present invention are compounds that are capable of forming polyurethane polymers. Polyurethane-forming compounds include, for example, polyurethane prepolymers. Prepolymers useful in the practice of the present invention are prepared by the reaction of active hydrogen compounds with any amount of isocyanate in excess material relative to active hydrogen material. The isocyanate functionality can be present in an amount of from about 0.2 wt % to about 40 wt %. A suitable prepolymer can have a molecular weight in the range of from about 100 to about 10,000. Prepolymers useful in the practice of the present invention should be substantially liquid under the conditions of dispersion.
Active hydrogen compounds can be described as compounds having functional groups that contain at least one hydrogen atom bonded directly to an electronegative atom such as nitrogen, oxygen or sulfur. Suitable active hydrogen compounds can be polyols of molecular weight of less than about 6000.
When the polymeric material is a polyurethane compound, the aqueous dispersed polymeric composition can include a chain extender. A chain extender is used herein to build the molecular weight of the polyurethane prepolymer by reaction of the chain extender with the isocyanate functionality in the polyurethane prepolymer, i.e., chain extend, the polyurethane prepolymer. A suitable chain extender is typically a low equivalent weight active hydrogen containing compound, having about 2 or more active hydrogen groups per molecule. The active hydrogen groups can be hydroxyl, mercaptyl, or amino groups. An amine chain extender can be blocked, encapsulated, or otherwise rendered less reactive. Other materials, particularly water, can function to extend chain length and so are chain extenders for purposes of the present invention. Polyamines are preferred chain extenders. It is particularly preferred that the chain extender be selected from the group consisting of amine terminated polyethers such as, for example, Jeffamine D400 from Huntsman Chemical Company, amino ethyl piperazine, 2-methyl piperazine, 1,5-diamino-3-methyl-pentane, isophorone diamine, ethylene diamine, diethylene triamine, triethylene tetramine, triethylene pentamine, ethanol amine, lysine in any of its stereoisomeric forms and salts thereof, hexane diamine, hydrazine and piperazine. In the practice of the present invention, the chain extender is often used as a solution of chain extender in water.
Small amounts of chain extender can be advantageously used. Generally, the chain extender is employed at a level sufficient to react with from about zero (0) to about 100 percent of the isocyanate functionality present in the prepolymer, based on one equivalent of isocyanate reacting with one equivalent of chain extender. It can be desirable, under certain conditions, to allow water to act as a chain extender and react with some or all of the isocyanate functionality present
A catalyst can be used to promote the reaction between a chain extender and an isocyanate. Suitable catalysts include tertiary amines, organometallic compounds, similar compounds, and mixtures thereof. For example, suitable catalysts include di-n-butyl tin bis(mercaptoacetic acid isooctyl ester), dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin sulfide, stannous octoate, lead octoate, ferric acetylacetonate, bismuth carboxylates, triethylenediamine, N-methyl morpholine, similar compounds, and mixtures thereof. An amount of catalyst is advantageously employed such that a relatively rapid cure to a tack-free state can be obtained. If an organometallic catalyst is employed, such a cure can be obtained by using from about 0.01 to about 0.5 parts per 100 parts of the polyurethane-forming composition, by weight. If a tertiary amine catalyst is employed, the catalyst preferably provides a suitable cure using from about 0.01 to about 3 parts of tertiary amine catalyst per 100 parts of the polyurethane-forming composition, by weight. Both an amine type catalyst and an organometallic catalyst can be employed in combination.
The present invention can include other filler materials. The filler material can include conventional fillers such as milled glass, calcium carbonate, aluminum trihydrate, talc, bentonite, antimony trioxide, kaolin, fly ash, or other known fillers. A suitable filler loading in a polyurethane dispersion can be from about 100 to about 1000 parts of filler per 100 parts of the polyurethane compound. Preferably, the filler material can be loaded in an amount of at least about 200 pph (phr), more preferably at least about 300 pph, most preferably at least about 400 pph.
The present invention can include a filler wetting agent. A filler wetting agent generally renders the filler material compatible with a polyurethane-forming composition. Useful wetting agents include phosphate salts such as sodium hexametaphosphate. A filler wetting agent can be included in a polyurethane-forming composition of the present invention at a concentration of at least about 0.5 parts per 100 parts of filler, by weight
The present invention can include other components, such as surfactants, blowing agents, frothing agents, defoamers, fire retardants, pigments, antistatic agents, reinforcing fibers, antioxidants, preservatives, acid scavengers, and the like. Useful surfactants include cationic and anionic surfactants. Examples of anionic surfactants include sulfonates, carboxylates, and phosphates. Examples of cationic surfactants include quaternary amines.
Surfactants can be either external or internal. External surfactants are surfactants are not chemically reacted into the polymer during dispersion preparation. Internal surfactants are chemically reacted into the polymer during dispersion preparation. A surfactant can be included in an amount ranging from about 0.01 to about 20 parts per 100 parts by weight of polyurethane component.
Examples of suitable blowing agents are gases such as air, carbon dioxide, nitrogen, argon, and helium; liquids such as water and volatile halogenated alkanes; and azo-blowing agents such as azobis(formamide). Volatile halogenated alkanes include the various chlorofluoromethanes and chlorofluoroethanes. The use of a gas as a blowing or frothing agent is preferred. Particularly preferable is the use of air as a blowing or frothing agent. A frothing agent can differ from a blowing agent in that frothing agents are typically introduced by mechanical introduction of a gas into a liquid to froth the polymeric composition.
A polyurethane dispersion of the present invention can be stored for later application to the back of a carpet. Storage for this purpose requires that the dispersion be storage-stable. Alternatively, the polyurethane dispersion can be applied in a continuous manner to the back of a carpet primary backing. That is, the dispersion can be applied to the back of a carpet as the dispersion is obtained. Polyurethane dispersions applied to a carpet in a continuous manner are not required to be storage-stable, and can have higher solids content and/or larger mean particle size than typical storage-stable polyurethane dispersion formulations.
A suitable storage-stable polyurethane dispersion as defined herein is any polyurethane dispersion having a mean particle size of less than about 5 microns; a more preferable mean particle size is less than about 1 micron. A polyurethane dispersion that is not storage-stable can have a mean particle size of greater than 5 microns. For example, a suitable dispersion can be prepared by mixing a polyurethane prepolymer with water and dispersing the prepolymer in the water using a commercial blender. Alternatively, a suitable dispersion can be prepared by feeding a prepolymer into a static mixing device along with water, and dispersing the water and prepolymer in the static mixer. Continuous methods for preparing aqueous dispersions of polyurethane are known and can be used in the practice of the present invention. For example, U.S. Pat. Nos. 3,437,624; 4,092,286; 4,237,264; 4,742,095; 4,857,565; 4,879,322; 5,037,864; and 5,221,710 describe continuous processes useful for obtaining aqueous polyurethane dispersions. In addition, a continuous process for preparing an aqueous polyurethane dispersion having a high internal phase ratio is described in U.S. Pat. No. 5,539,021, incorporated herein by reference.
The steps used in preparing a polyurethane carpet backing can be carried out in a continuous manner. For example, the prepolymer can be prepared from a suitable active hydrogen-containing compound in a continuous manner. The prepolymer can be loaded directly into a mixing device with water to obtain an aqueous dispersion. Ultimately, the aqueous polyurethane dispersion can be applied to a carpet primary backing in a continuous manner to obtain a polyurethane-backed carpet
In preparing polyurethane-backed carpets according to the present invention, an aqueous polyurethane dispersion is applied as a layer of preferably uniform thickness onto one surface of a carpet primary backing. Aqueous polyurethane dispersions of the present invention can be applied as a precoat, a laminate layer, or a foam layer. Polyurethane precoats, laminate layers, and foam layers can be prepared by methods known in the art. Precoats, laminate layers and foam layers prepared from latexes are described in P. L. Fitzgerald, xe2x80x9cIntegral Latex Foam Carpet Cushioningxe2x80x9d, J. Coat Fab. 1977, Vol. 7 (pp. 107-120), and in R. P. Brentin, xe2x80x9cLatex Coating Systems for Carpet Backingxe2x80x9d, J. Coat. Fab. 1982, Vol. 12 (pp. 82-91). In preparing a frothed polyurethane backing (frothing), it is preferred to mix all components and then blend a gas into the mixture, using equipment such as an Oakes or Firestone foamer.
The polyurethane-forming composition can be applied to one surface of a carpet primary backing before it cures to a tack-free state. Alternatively, a polyurethane dispersion containing no unreacted isocyanate functionality can be applied, thereby removing the need to cure the polymer. Typically the polyurethane-forming composition is applied to the surface attached to a primary backing.
The composition may be applied and gauged to the carpet primary backing using equipment such as a doctor knife, air knife, or extruder. Alternatively, the composition may be applied by (1) forming it into a layer on a moving belt or other suitable apparatus, (2) dehydrating or partially curing, and (3) finally, marrying it to the carpet primary backing. It may be married to the carpet primary backing with equipment such as a double belt laminator (also known as double band) or a moving belt with an applied foam cushion.
The amount of polyurethane-forming composition used can vary widely, from about 5 to about 500 ounces per square yard, depending on the characteristics of the textile. After the layer is applied and gauged, water is removed from the dispersion and the layer can be cured using heat from any suitable heat source such as an infrared oven, a convection oven, or heating plates.
A styrene-butadiene latex useful for practicing the present invention is disclosed in P. L. Fitzgerald, xe2x80x9cIntegral Latex Foam Carpet Cushioningxe2x80x9d, J. Coat. Fab. 1977, Vol. 7 (pp. 107-120) and in R. P. Brentin, xe2x80x9cLatex Coating Systems for Carpet Backingxe2x80x9d, J. Coat. Fab. 1982, Vol. 12 (pp. 82-91), both incorporated herein by reference. A styrene-butadiene-vinylidene chloride latex useful for practicing the present invention is disclosed in U.S. Pat. No. 5,741,393, incorporated herein by reference.
U.S. Pat. No. 5,770,660, incorporated herein by reference, discloses a method for preparing a butadiene-acrylonitrile latex that is useful for practicing the present invention. U.S. Pat. Nos. 3,644,262 and 4,164,489, incorporated herein by reference, disclose methods for preparing ethylene-vinyl-acetate latexes that are useful for practicing the present invention. U.S. Pat. No. 5,591,806, incorporated herein by reference, discloses a method for preparing an ethylene acrylic acid aqueous dispersion that is useful for practicing the present invention.
U.S. Pat. Nos. 3,890,261 and 5,661,205, incorporated herein by reference, disclose methods for preparing chloroprene latexes useful for practicing the present invention. U.S. Pat. No. 5,380,785, incorporated herein by reference, discloses a method for preparing a butyl acrylate-acrylonitrile-styrene latex that is useful for practicing the present invention. U.S. Pat. Nos. 4,689,256 and 5,300,551, incorporated herein by reference, disclose methods for preparing vinyl chloride polymer latexes that are useful in practicing the present invention.
U.S. Pat. No. 5,591,806, incorporated herein by reference, discloses a method for preparing a ethylene acrylic acid copolymer latex that is useful in practicing the present invention. U.S. Pat. No. 4,714,728, incorporated herein by reference, discloses a method for preparing an aqueous dispersion of acidic ethylene interpolymers that are useful in practicing the present invention.
U.S. Pat. No. 4,228,058, incorporated herein by reference, discloses a method for preparing a mixture of vinylidene chloride latex and a styrene-butadiene latex useful in practicing the present invention. Other methods of preparing useful aqueous dispersed polymeric compositions would be readily apparent to a person of ordinary skill in the art in view of this disclosure. Those methods and aqueous dispersed polymeric compositions are within the scope of the invention with regard to preparing useful aqueous dispersed polymeric compositions.
The inorganic fillers of the present invention include calcium carbonate, calcium sulfate, kaolin, lignite fly ash, silica, talc, feldspar, mica, glass spheres, wollastonite, aluminum trihydrate, aluminum oxide, fiber glass, similar compounds, and mixtures thereof. In the present invention, the preferred inorganic filler is calcium carbonate.
The hydrophobic acids and salts of hydrophobic acid for treating the inorganic filler mixtures of the present invention include C4 to C22 acids and salts thereof. Also, the acids can be saturated or unsaturated. Examples of such acids include, but are not limited to, butyric acid, hexanoic acid, octanoic acid, decanoic acid, dodecanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, stearic acid, linolenic acid, similar compounds, and mixtures thereof. In the present invention, the preferred acid-treated inorganic filler is stearic acid-treated calcium carbonate.
The salts of any of the hydrophobic acids described herein, alone or in admixture with any other salt or hydrophobic acid, can be useful in the practice of the present invention. Preferably, the salt is selected from the group consisting of calcium stearate, lithium stearate, and zinc stearate, and more preferably, zinc stearate, and most preferable, wettable zinc stearate. Wettable zinc stearate is easily and uniformly compounded with a polyurethane dispersion and yields superior spill resistance. The preferred inorganic filler and hydrophobic salt combination is calcium carbonate with zinc stearate.
Other useful hydrophobic acids or hydrophobic acid salts include gum rosin, wood rosin, tall oil rosin, abietic acid, oxidized polyethylene containing carboxylic acid groups, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, polyolefins grafted, with unsaturated carboxylic acids, polyolefins grafted with anhydrides such as maleic anhydride, methacrylic acid, maleic acid, fumaric acid, acrylic acid, and the like.
The hydrophobic acid or a salt thereof can be added to the carpet backing formulation mixture in an amount of from about 0.025% weight by weight (w/w) to about 10% (w/w), based on the total weight of solids present in the mixture. Preferably the hydrophobic acid or its salt is added in an amount of from about 0.5% (w/w) to about 6.0% (w/w), more preferably form about 1.0% (w/w) to about 3.0% (w/w) most preferably from about 1.0% (w/w) to about 2.0% (w/w), based on total solids.
The inorganic filler can also be surface treated with the hydrophobic acid or its salt prior to introduction into the carpet backing dispersion formulation. This may be accomplished in a variety of ways. For example, the hydrophobic acid may be surface coated onto the filler in a high intensity mixer above the melting point of the hydrophobic acid. Another method involves the spraying of the aqueous dissolved or dispersed hydrophobic acid or its salt onto the agitated filler.
In an alternate embodiment, the aqueous dispersed polymeric composition comprises an aqueous dispersed polymeric material and a treated inorganic filler, having been treated with a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof.
In another alternate embodiment of the present invention, a kit for preparing a spill resistant carpet backing is provided. It comprises an aqueous dispersed polymeric material, an inorganic filler, and a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof. Alternatively, the kit can comprise an aqueous dispersed polymeric material and a treated inorganic filler, having been treated with a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof.
The present invention also provides a method for preparing a spill resistant carpet backing comprising (a) mixing an inorganic filler with an aqueous dispersed polymeric material and (b) admixing a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof. Alternatively, the method can comprise (a) treating an inorganic filler with a hydrophobic compound selected from the group consisting of a hydrophobic acid, a salt of a hydrophobic acid, and mixtures thereof and (b) mixing the treated inorganic filler with an aqueous dispersed polymeric material.